REACTIVE LIPOSOMES ENCAPSULATING A GLUCOSE OXIDASE-PEROXIDASE SYSTEM WITH ANTIBACTERIAL ACTIVITY

Liposomes were prepared from phospholipid mixtures of dipalmitoylphosp hatidylcholine (DPPC) and phosphatidylinositol (PI), encapsulating the enzymes glucose oxidase (GO) and GO in combination with horse radish peroxidase (HRP) by both extrusion (VET) and reverse-phase evaporation (REV). The optimum level of PI in DPPC/PI liposomes for targeting to biofilms of the oral bacterium Streptococcus gordonii has been establi shed. The liposomes were characterised in terms of the content and act ivity of the encapsulated enzymes. The antibacterial activity of these 'reactive' liposomes arising from hydrogen peroxide and oxyacids in t he presence of the substrates glucose and iodide ions, after targeting to the biofilms, were measured both as a function of liposome-biofilm incubation time and incubation time with the substrates. Bacterial in hibition increases with both liposome-biofilm and substrate-biofilm in cubation time and with the extent of enzyme encapsulation. The reactiv e liposomes also display antibacterial activity in the presence of sal iva. The reactive liposomes have potential value in the context of ora l hygiene.